A stupid, very stupid bug in favourites configuration

This is new from VC 1.14 and above. When I define encrypted file container, assign default mount letter and set it up for mount upon logon (+when host media is connected), I'm getting this stupid and unlogic error after logon (four times):

As noted in the 1.16 release note, the following change was introduced:

By default, don’t try to mount using empty password when default keyfile configured or keyfile specified in command line. Add option to restore the old behavior.

If mounting using empty password is needed, explicitly specify so in the command line using: /p ""

If you need VeraCrypt to try to mount using an empty password when default keyfiles are configured, you have to explicitly check the option "Try first to mount with an empty password" in the menu "Settings -> Default Keyfiles". The screenshot
below show this.
If you are using the command line, you can either specify an empty password explicitly or you can use the new switch "/tryemptypass y" documented here:
https://veracrypt.codeplex.com/wikipage?title=Command%20Line%20Usage#tryemptypass

This option was added because implicitly trying to mount using an empty password was penalizing users who combine default keyfiles and passwords, which is the recommended secure approach.

Concerning the bug and issue that appear on each release, this is due to the impossibility to test all possible configuration: the number of testers is quiet low even though betas are published regularly. I encourage everybody to participate in the tests of
the beta version published in
https://sourceforge.net/projects/veracrypt/files/VeraCrypt%20Nightly%20Builds/. They all come with release notes indicating the introduced changes.
Huge efforts are made to bring useful features to the maximum number of users and to fix all issues that may exist. Outside help from the community to test and validate all changes is more than welcomed.

I was not able to reproduce your issues: everything work as expected on my side.

I have done a video showing a favorite volume being mount with default keyfile using the command line switches you posted above. It also show the effect of activating the "Try first with an empty password" in the GUI. Here is the link:
https://www.youtube.com/watch?v=_CXP2e6JdKc

Are you doing something different? What should I do to reproduce your issues?

@tukan: did you see my video above where I demonstrate the same configuration as you and it is working. Do you see something different?

Also, it is possible you are affected by the Windows Mount Manager cache issue that I explained in other posts. For that, you have to look at the "HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices" and remove any entry that has the name "\Dos\Devices\A:"
or "\Global??\A:".
Here an updated version of the instructions I gave previously:

Check the registry key "HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices" using regedit. Scroll down and you'll find entries starting with "\DosDevices\" "\GLOBAL??\" which
indicate the drive letters that are taken by the system. Before mounting any volume, double click on each one and remove the ones contains the name "VeraCrypt" and "TrueCrypt".
Also, there are other entries whose name start with "#{" and "\??\Volume{": double click on each one of them and remove the ones whose data value contains the name "VeraCrypt" and "TrueCrypt".